How do electron double slit experiments block electrons if they penetrate thin materials?

[snowdogging]

I understand how Young used the double slit experiment to prove that light travels in a wave but I am confused on the application of the double slit experiment to electrons.

I read somewhere that Young used a 200 angstrom thick sheet of silver as a reflection medium for the light. But, what is used in the electron experiment to block the electrons so that they only go through the slit? I ask this because beta radiation is often used as a measuring tool for metal thickness since it passes through easily. I also read somewhere that 85% of the electrons in the experiment were hitting the target which, unless the slits are very large, makes me believe that the electrons are passing through the medium.

So if the electrons are passing through the medium, wouldn't they display a wave pattern simply due to interference from the mediums atoms, similar to a Plinko game? http://en.wikipedia.org/wiki/Plinko

Alternatively, if the medium was thick enough to stop electrons wouldn't it also be so thick that the electrons would bounce off the wall of the slit and create a similar wave pattern?

Anyway, this is just something that was bugging me today and I would appreciate if someone could set me straight.

 

[unusualname]

You can close one of the slits and the interference pattern doesn't appear.

That should remove all the doubts about wall transparency/bouncing effects being relevant :)

 

[snowdogging]

Ah now I got it! At least that far... :)

Thanks!